Flat-Bottom Polymer Vials for Lyophilization Heat and Barrier Control
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Solution Overview
Problem
Existing glass vials for pharmaceutical lyophilization face issues such as contamination, breakage, and non-uniform surface chemistry, while plastic vials suffer from gas permeability and leachables, making them unsuitable for lyophilization applications.
Innovation Solution
Development of polymer vials with a substantially flat bottom and sidewalls, produced through injection stretch blow molding, using a mold with a flat base mold and precise control of sidewall thickness, and application of PECVD water barrier coatings to enhance thermal efficiency and gas barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass vials are used for pharmaceutical lyophilization, then chemical inertness and clarity are improved, but breakage risk and contamination from metal ions increase
Solution Approach 1:
The patent changes the material parameter from glass to cyclic olefin polymer (COP), transforming the container from fragile to impact-resistant while maintaining chemical inertness through proper material selection and processing
Solution Approach 2:
The patent uses composite construction with COP as the base material and applies silicon oxide coating layers to combine the impact resistance of polymer with the chemical inertness and non-leaching properties of glass-like surfaces
2Strength
If plastic vials are used instead of glass, then breakage resistance is improved, but gas permeability and leachables increase
Solution Approach 1:
The patent applies thin film coating layers (silicon oxide) on the interior surface of the flexible polymer vial to create a barrier against gas permeability while maintaining the overall flexibility and impact resistance of the polymer container
Solution Approach 2:
The patent creates a composite structure combining COP polymer with silicon oxide coating layers, where the polymer provides mechanical strength and the inorganic coating provides gas barrier properties and chemical inertness
3Ease of manufacture
If conventional blow molding is used for plastic vials, then manufacturing simplicity is improved, but dimensional tolerances and side-wall thickness uniformity worsen
Solution Approach 1:
The patent uses a preform (test tube) as an intermediate form that is subsequently heated and blown into the final vial shape. This preliminary formation step allows for precise control of material distribution and wall thickness before the final blowing operation
Solution Approach 2:
The patent controls the temperature parameter during the blowing process, heating the preform to a specific range to achieve optimal material flow and wall thickness uniformity, then rapidly cooling to set the dimensions with high precision
4Strength
If domed bases are used in conventional vials, then structural strength is improved, but thermal efficiency during lyophilization worsens
Solution Approach 1:
The patent inverts the conventional design by using a flat base instead of a domed base, changing the curvature from convex to planar to maximize thermal contact area with the lyophilization shelf, thereby improving heat transfer efficiency while maintaining adequate structural strength through the overall vial design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The polymer vials provide improved thermal efficiency, consistent dimensional tolerances, and reduced gas permeability, ensuring stable storage and lyophilization of biologics without contamination, addressing the limitations of glass and plastic vials.
Implementation Method 1
stretching the preform with the mandrel to extend an end of the preform
Implementation Method 2
blowing gas into the preform such that the preform expands within the molding space
Implementation Method 3
application of PECVD water barrier coatings to enhance thermal efficiency and gas barrier properties
Data Source
AI summary
Disclosed are polymer vials and injection stretch blow molding methods for making the same. A polymer vial has a base having a base surface area and a sidewall extending up from the base. The base and sidewall define an interior configured to house product, the sidewall narrowing at an upper section of the vial to form a neck leading to an opening that provides access to the interior. The vial is optionally round and symmetrical about a central axis, a lower portion of the sidewall including a first surface that is outwardly curved along a first radius having an imaginary center positioned within the vial. The base is positioned below the first surface and is substantially flat such that at least 80% of the base surface area has a standing base surface occupying a single plane.